Knowledge Check

True of false: the following is the current diagnostic criteria for polycythemia vera.

a
True
b
False
These are the criteria from WHO 2008.

TypeWHO 2008WHO 2016
MajorHb > 18.5 M, Hb > 16.5 F or other evidence of increased red cell volumeHb > 16.5 M, Hb > 16.0 F, Hct >49% M, Hct > 48% F or other evidence of increased red cell volume
Presence of JAK2 V617F or other functionally similar mutation such as JAK2 exon 12 mutationPresence of JAK2V617F or JAK2 exon 12
mutation
N/ABM biopsy showing hypercellularity for age with trilineage growth (panmyelosis) including prominent erythroid, granulocytic, and megakaryocytic proliferation with pleomorphic,
mature megakaryocytes (differences in size)
MinorSerum erythropoietin level below the reference range for normalSubnormal serum erythropoietin level
Endogenous erythroid colony formation in vitro
Bone marrow biopsy showing hypercellularity for age with trilineage growth (panmyelosis) with prominent erythroid, granulocytic, and megakaryocytic proliferation
DiagnosisDiagnosis of PV requires the presence of both major criteria and one minor criterion or the presence of the first major criterion together with two minor criteriaDiagnosis of PV requires meeting either all 3 major criteria, or the first 2 major criteria and the minor criterion*
A comparison of the WHO 2008 and 2016 diagnostic criteria for polycythemia vera (PV). the major differences are highlighted in bold red. First, the threshold for Hb/Hct has been lowered so that patients with masked PV are more likely to be diagnosed. Second, bone marrow biopsy is a minor criterion in the 2008 panel, but a major criterion in 2016. However, the 2016 diagnostic criteria note that bone marrow biopsy may not be required in those with hemoglobin levels >18.5 g/dL in men (hematocrit, 55.5%) or >16.5 g/dL in women (hematocrit, 49.5%) Finally, the 2016 criteria do not include endogenous erythroid colony formation in vivo. *Criterion number 2 (BM biopsy) may not be required in cases with sustained absolute erythrocytosis: hemoglobin levels >18.5 g/dL in men (hematocrit, 55.5%) or >16.5 g/dL in women (hematocrit, 49.5%) if major criterion 3 and the minor criterion are present. However, initial myelofibrosis (present in up to 20% of patients) can only be detected by performing a BM biopsy; this finding may predict a more rapid progression to overt myelofibrosis (post-PV MF).

Sort the parameters (top) according to the appropriate 2016 PV diagnostic criteria buckets (bottom):

CALR mutation
JAK2V617F
Hct>49 (M)/48% (F)
BM biopsy
Subnormal serum erythropoietin level
Hb>16.5 (M)/16.0 (F)
Hb>18.5 (M)/18.0 (F)
Endogenous erythroid colony formation in vitro
Elevated LDH
Minor crirteria
Major criteria
Not a criterion

Consider the following patients:

TypePatient 1 (male)Patient 2 (female)Patient 3 (male)Patient 4 (female)
Hb16.3 g/dL21 g/dL17 g/dL17.5 g/dL
JAK2 V617FPositiveNegativePositiveNot done
BM biopsyNot doneNot doneNot doneConsistent with PV
Serum erythropoietin levelLowNormalLowLow

Which of these patient(s) meets the WHO 2016 diagnostic criteria for polycythemia vera?

a
Patient 1
Requires bone marrow biopsy
b
Patient 2
c
Patient 3
d
Patient 4

True or false: the white cell count and platelet count may be elevated in patients with polycythemia vera, but are not part of the diagnostic criteria:

a
True
b
False